The impact of emotion intensity on recognition memory: Valence polarity matters

Self-reference and emotional reaction drive aesthetic judgment

Traditional philosophical inquiry, and more recently neuroscientific studies, have investigated the sources of artworks' aesthetic appeal. A substantial effort has been made to isolate the objective features contributing to aesthetic appreciation. While variables such as contrast or symmetry have been shown to robustly impact aesthetic judgment, they only account for a small portion of the intersubjective variability in aesthetic ratings. Recent multiprocess model of aesthetic appreciation could accommodate this finding by proposing that evaluative processes based on self-reference underpin the idiosyncrasy of aesthetic judgment. We tested this hypothesis in two behavioral studies, that were basically conceptual replications of our previous work, in which we took advantage of the self-reference effect on memory. We also tried to disentangle the role of self-reference and emotional reaction to artworks in guiding aesthetic judgments, by comparing an aesthetic judgment encoding condition to a self-reference condition (Study 1), and an emotional evaluation condition (Study 2). We show that artworks encoded in an aesthetic judgment condition exhibit a similar mnesic advantage compared to both the self-reference and the emotional evaluation encoding conditions. Moreover, retrospective emotional judgment correlates with both self-reference and aesthetic judgments ratings. These results suggest that a basic mechanism, appraisal of self-relevance, could ground aesthetic judgments.

Role of facial familiarity and emotional expression intensity in ensemble emotion perception

When looking at groups of people, we can extract information from the different faces to derive properties of the group, such as its average facial emotion, although how this average is computed remains a matter of debate. Here, we examined whether our participants' personal familiarity with the faces in the group, as well as the intensity of the facial expressions, biased ensemble perception. Participants judged the average emotional expression of ensembles of four different identities whose expressions depicted either neutral, angry, or happy emotions. For the angry and happy expressions, the intensity of the emotion could be either low (e.g., slightly happy) or high (very happy). When all the identities in the ensemble were unfamiliar, the presence of any high intensity emotional face biased ensemble perception towards its emotion. However, when a familiar face was present in the ensemble, perception was biased towards the familiar face's emotion regardless of its intensity. These findings reveal that how we perceive the average emotion of a group is influenced by both the emotional intensity and familiarity of the faces comprising the group, supporting the idea that different faces may be weighted differently in ensemble perception. These findings have important implications for the judgements we make about a group's overall emotional state may be biased by individuals within the group.

The ERP correlates of color-based center-surround inhibition in working memory

The color-based center-surround inhibition (CSI) in working memory (WM) refers to that remembering a color inhibits the memory of similar colors but not of distinct colors. This study aimed to investigate the neural activity of color-based CSI in WM. Two WM items (distance 0°, 10°, 20°, 30°, 40°, 50°, or 60° in color space) were displayed sequentially, then one of them was retrieved to compare with a later probe. Behavioral results revealed that participants showed longer RTs for distances 20° and 30° than distances 0° and 40°, suggesting a CSI between similar items. ERP results revealed that: 1) WM item-induced late positive component (LPC) was more positive for distance 30° than the other distances, suggesting an enhanced resource allocation process for encoding similar items; 2) Cue-induced LPC was more positive for distances 20° and 30° than distances 0° and 60°, suggesting a greater difficulty for retrieving similar items; Cue-induced contingent negative variation was less negative for distance 20° than distances 40°, 50°, and 60°, suggesting a reduced response preparation process during retrieving similar items; 3) Probe-induced LPC was more positive for distances 20° and 30° than distances 50° and 60°, suggesting a greater effort for comparing probe with one item retrieved from two similar items. These results revealed a colored-based CSI during WM encoding and retrieval processes. An enhanced top-down control might be required to resolve the greater interference between similar items than identical or distinct items conditions.

The influence of negative emotional intensity on dual-processing recognition

Dual-processing theory assumes recognition memory involves two distinct processes: familiarity and recollection. Although the influence of emotional intensity on memory has been investigated, it remains unclear whether the influence of negative stimuli depends on familiarity or recollection. This study recorded event-related potentials as participants performed a modified remember/know procedure with highly negative, mildly negative, and neutral stimuli. The results showed that, relative to highly negative stimuli, mildly negative and neutral stimuli showed increased mean discrimination for responses of 'know' in the following pattern: highly negative < mildly negative < neutral. Neutral stimuli enhanced the frontal old/new effect. Relative to mildly negative and neutral stimuli, highly negative stimuli showed increased mean discrimination for responses of 'remember', and enhanced the parietal old/new effect. These results suggested negative emotional intensity influences recollection and familiarity differently, as recognition of highly negative stimuli depends on recollection, and recognition of neutral stimuli depends on familiarity.

Interactions of Emotion and Self-reference in Source Memory: An ERP Study

The way emotional information is encoded (e.g., deciding whether it is self-related or not) has been found to affect source memory. However, few studies have addressed how the emotional quality and self-referential properties of a stimulus interactively modulate brain responses during stimulus encoding and source memory recognition. In the current study, 22 participants completed five study-test cycles with negative, neutral, and positive words encoded in self-referential versus non-self-referential conditions, while event-related potentials of the electroencephalogram were recorded. An advantage of self-referential processing in source memory performance, reflected in increased recognition accuracy, was shown for neutral and positive words. At the electrophysiological level, self-referential words elicited increased amplitudes in later processing stages during encoding (700-1,200 ms) and were associated with the emergence of old/new effects in the 300-500 ms latency window linked to familiarity effects. In the 500-800 ms latency window, old/new effects emerged for all valence conditions except for negative words studied in the non-self-referential condition. Negative self-referential words also elicited a greater mobilization of post-retrieval monitoring processes, reflected in an enhanced mean amplitude in the 800-1,200 ms latency window. Together, the current findings suggest that valence and self-reference interactively modulate source memory. Specifically, negative self-related information is more likely to interfere with the recollection of source memory features.

Neural substrates of long-term item and source memory for emotional associates: An fMRI study

Since Tulving's influential work on the distinction between familiarity and recollection-based retrieval, numerous studies have found evidence for differential contribution of these retrieval mechanisms on emotional episodic memory. Particularly, retrieval advantage for emotional, compared to neutral, information has been related to recollection-, but not familiarity-mediated processes. Neuroimaging studies suggest that this recollection-based retrieval for emotional information is related to stronger engagement of regions in the medial temporal lobe (MTL), posterior parietal cortex (PPC), and prefrontal cortex (PFC). In the present study, we investigated neural correlates related to long-term memory of neutral information that has been associated with emotional and neutral contexts, using functional magnetic resonance imaging (fMRI). During encoding, different neutral objects integrated with emotional or neutral scenes were presented. One week later, the encoded objects were intermixed with new ones and participants had to indicate whether the objects were previously seen or not, using the Remember/Know procedure (item memory). Furthermore, memory for the correct scene background category was also tested (contextual source memory). First, replicating previous findings, we observed a preference for recollection-dependent memory retrieval versus familiarity-dependent memory retrieval for those neutral objects encoded in emotional compared to neutral contexts. Second, consistent with these behavioral effects, objects encoded with emotional, compared to neutral, scenes produced larger memory-related activity in recollection-sensitive brain regions, including PPC and PFC regions. Third, correctly retrieved emotional compared to neutral contextual information was associated with increased activity in these brain areas. Together, these results suggest that memory for information encoded in emotional contexts is remarkably robust over time and mediated by recollection-based processes.

Post-encoding positive emotion impairs associative memory for English vocabulary

There is evidence that emotion induced during encoding impairs associative memory (e.g., Bisby, Horner, Bush, & Burgess, 2018), yet the effect of post-encoding emotion (particularly positive emotion) on associative memory remains largely unclear. Two experiments were conducted to examine the effect of post-encoding positive emotion on associative memory for English vocabulary. In Experiment 1, high school students memorized Chinese definitions of a list of English words, immediately recalled the Chinese definitions, watched a neutral or comic video, and took a delayed memory test 25 minutes after encoding. The result showed a significant impairing effect of post-encoding positive emotion on memory for Chinese definitions. In Experiment 2, primary school students encoded English words with their associative pictures, took an immediate test where, on each trial, they were asked to choose the correct English word that matches a picture. Following the test, they watched a neutral or comic video, and took a memory test 10 minutes after encoding. Consistent with Experiment 1, Experiment 2 showed an impairing effect of positive emotion. Taken together, these findings support the hypothesis that post-encoding positive emotion can impair associative memory, providing important implications for acquisition of vocabulary of English as a foreign language.

Brain-Derived Neurotrophic Factor Val66Met Polymorphism Is Associated With a Reduced ERP Component Indexing Emotional Recollection

The Met allele of the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism is associated with reduced functioning of the amygdala and hippocampus. It has been linked to major psychiatric conditions, including depression and post-traumatic stress disorder, and is associated with deficits in episodic memory. The precise mechanisms of the BDNF gene’s influence on emotional memory are not well characterized, especially its impact on recognition. Two electrophysiological experiments of emotional memory were run on two independent samples genotyped for BDNF Val66Met. Event-related potentials (ERPs) corresponding to the recognition of negative and neutral words (Experiment 1, N = 37) and negative and positive words (Experiment 2, N = 23) were recorded, and the late parietal component (LPC), typically associated with conscious recollection, was analyzed. In Experiment 1, a reduced LPC was observed in Met carriers (N = 12) compared to Val homozygotes (N = 25) in the negative condition, but the group difference was not present in the neutral condition. In Experiment 2, the reduced LPC was seen in Met carriers (N = 12) compared to Val homozygotes (N = 11) across both conditions. This study provides the first evidence of an association between the BDNF Val66Met genotype and the late parietal electrophysiological component, suggesting that the conscious experience of emotional recollection may differ according to BDNF Val66Met genotype. Further, these results suggest that this effect is likely due to emotional arousal rather than valence polarity. Results were discussed with reference to the possible mechanisms by which emotional recollection deficits may contribute to psychopathology.

The mediational role of distracting stimuli in emotional word recognition

Emotions are considered distractions that often prompt subsequent actions. In this way, the aim of this work was to examine the role of distracting stimuli on the relationship of RT and accuracy. In order to do that, a word recognition task was carried out in which emotional valence was manipulated. More precisely, a mediational model, testing how changes in distracting stimuli mediate RT predicting accuracy across emotional conditions, was carried out. The results suggest that changes in task demands should distract from the secondary task to the extent that these task demands implicate and affect accuracy. Moreover, the distracting task seems to mediate between accuracy and the target task under emotional stimuli, showing the negative distracting condition to be the most remarkable effect. Furthermore, neutral distracting latencies did not affect accuracy. Understanding the mechanisms by which emotion impairs cognitive functions has important implications in several fields, such as affective disorders. However, the effects of emotion on goal-directed cognitive processing remain unclear.

Retention interval modulates the effect of negative arousing pictures on recognition memory

This study examined the modulation of retention interval in the effect of emotion as elicited from negative and positive arousing pictures on recognition memory. Participants underwent seven encoding sessions and one testing session. The encoding sessions were separated by certain lengths of intervals such that there were seven levels of time gaps between encoding and testing. In each encoding session, participants learned a list of 30 pictures (including 10 neutral, 10 positive and 10 negative pictures). In the testing session, they were presented with a list of 210 old and 210 new pictures and made "old/new" and "remember/know" judgements. The results showed that negative arousing pictures enhanced overall recognition in the 2-week interval and enhanced recollection in both the 2-week and 3-week intervals. However, neither negative nor positive arousing pictures had any effect on familiarity regardless of retention interval. The current study contributes to the literature by suggesting that longer retention intervals do not necessarily lead to more pronounced effects of negative arousing pictures and that the modulation of retention interval depends on the specific components of recognition memory.